Manufacture of indented, corrugated papers



Aug. 26, 1941. J. A. MGKEAGE 1 2,253,718

MANUFACTURE OF INDENTED. CORRUGATED PAPERS Filed Jan. 11; 1939 jzmm (m JZ/Wizmw Patented Aug. 26, 1941 UNITED STATES PATENT {)FFICE MANUFACTURE OF INDENTED, CORRUGATED PAPERS JohnA. McKeage, Brookline, Mass, assignor to Sherman Paper Products Corporation, Newton, Mass.,-a corporation of Massachusetts Application January 11, :1939, Serial No. 250,387 2 Claims. (01. l54-55) In accordance with Ives Reissue Patent No.

20,034, dated July 14, 1936, a corrugated paper product flexing readily across its corrugations is produced by creating indentures or recesses in the corrugations inwardly toward the plane paper ply along lines intersecting or crossing the corrugations at closely spaced intervals. A preferred embodiment of product disclosed in said reissue patent involves arrangement of the indentures or recesses in the corrugations along criss-crossing lines running diagonally across the corrugations, preferably running at angles of substantially 45 thereto.

In accordance with the present invention, a corrugated paper product of the desired flexibility in all directions across the corrugations is realized by locally indenting or breaking down the successive corrugations in such fashion that the lines or regions of indentation of the successive or adjacent corrugations are staggered relative to one another, with the lines of indentation in one corrugation preferably occurring substantially midway between the lines of indentation in an adjacent corrugation. In order to ensure a product possessed of the flexibility and resiliency or cushioning property desired therein, the lines of indentation in all of the successive corrugations should be appropriately spaced, namely, a disstance not less than about 1%" and not more than about Vz'f The indented corrugated paper product hereof may be fabricated'at high speeds with comparatively little, if any, tendency to distort or crush the corrugated paper portions lying in between the lines or regions of indentation or to wrinkle the plane paper ply serving as the backing or reinforcing medium. It might be remarked that the expression fcorrugated paper produc is used herein to denote a product or composite sheet including not only a corrugated paper ply but also a plane or fiat paper ply or equivalent flexible fabric adhesively or otherwise secured as a reinforcing medium to the corrugated P p Ply.

With the foregoing and other features and oh- I jects in view, the presentinvention will now be described in further detail with particular reference to the accompanying drawing, wherein,

Fig. 1 shows in perspective a fragment of an indented corrugated paper product embodying the present invention.

Fig. 2 is a plan view of a fragment of such product.

Fig. 3 represents an enlarged longitudinal sec-, tion through one of the indented corrugations along the line 33 of Fig. 1.

Fig. 4 depicts in perspective part of an indenting roll such as may be used for creating the indentations in the corrugated paper product hereof.

Fig. 5 illustrates one of the toothed rings or indentingelements entering into the roll assembly of Fig. 4.

Fig. 6 is an enlarged vertical section through one of the indenting teeth 0i. a toothed ring along the line 6-5 of Fig. 5. v

Fig. '7 represents a plan view of a modified form of indenting roll.

As appears in Fig. 1, the indented, corrugated paper product hereof comprises a plane paper ply ill-secured, as by suitable adhesive, to the corrugated paper ply H. It appears unnecessary to describe in detail the manufacture of the corrugated paper product prior to indenting its corrugated paper ply. Suflice it to say'that the ply Ill may be progressively withdrawn from a roll' accumulation and united with the corrugated ply l I after the latter ply has issued from the nip of a pair of corrugating rolls and has been treated with suitable adhesive on its valleyzones to con-' tact or lie next to the ply l0.

Once the two plies have been adhesively united to form the usual corrugated paper product, the successive corrugations of the corrugated ply are indented or broken down toward the plane p p r ply so that the lines or regions of indenture l2 in one corrugation are arranged in staggered relationship to the lines or regions of indentureli in an adjacent corrugation. It is preferable, as shown, that the lines of indenture in one corrugation occur substantially midway between the lines of indenture in a succeeding corrugation and that all the lines of indenture in'the successive corrugations are substantially perpendicular to the longitudinal lines definitive of the crests of the successive corrugations. The lines of indenture in each of the successive corrugations are advantageously spaced apart a distance falling within a range of about to about /2", as this makes for a'product possessed of the desired con-- posed, toothed rings l5.

' junctive properties of resiliency and flexibility across its corrugations.

The desired indentation of the successive corrugations in the corrugated ply may be accomplished by a suitable indenting roll which contacts with or operates upon the corrugated paper ply of a continuously moving'corrugated paper product while the plane paper ply of such product is being backed up or supported on a roll, or on a belt, or on a plate, or .by or on some other equivalent means. Thus, the indenting roll structure depicted in Fig. 4 comprises a steel core IE on .which is mounted a series of .juxta- The core I may be equipped with a spline i6 adapted to fit into a complemental recess i! in each of the rings i and thereby hold them against rotation thereon. The rings may be fastened together against iongitudinal movement of the core, as by longitudinal bolts 9 or some other suitable or equivalent means,

Each tooth l8 of a ring i5 is adapted to create a line of indentation l2 or H, as the case may be, in the corrugated ply; and, to this end, such tooth is preferably of an annular span or length at its edge slightly greater than the distance between the longitudinal crest lines of adjacent corrugations in the corrugated ply, thereby ensuring a line of indentation by each tooth substantially entirely across a corrugation. The recesses I! in adjacent toothed rings i5 are ,so located that when the rings are mounted on the core ll with the spline i6 entering into such recesses, a tooth in one ring is staggered relative to a tooth in an adjacent. ring, that is, occupies a position alongside the space I9 between the teeth of an adjacent ring, as appears clear from Fig. 4. The

toothed periphery of the roll of Fig. 4 should obviously extend over a longitudinal distance corresponding to the width of the corrugated paper product on which it is to act.

While not limited thereto, it is preferable that of tapering cross-sectional shape, as appears in Fig. 6 and the maximum annular span of such teeth and the intervening spaces in an annular series may conform to the dimensions already each indenting tooth! 'in a ring l5 present the cross-sectional shape appearing in Fig. 6. Thus, such tooth may taper steeply toward its outer or indenting edge I811, which may be left dull or flat so as to obviate possibility of cutting the corrugations as they are being indented. The maximum annular distance or space l9 between two successive teeth i8 in each of the indenting rings may advantageously be slightly less than the maximum annular width or span of each of the teeth themselves, since this ensures the desired line of indentation substantially completely across each corrugation, especially when; as already indicated, the outer or maximum annular width of each of the teeth It is slightly greater than the distance between the longitudinal crest lines of adjacent corrugations.

- In lieu of the indenting roll structure of Fig. 4,

' it is possible to use a roll whose periphery, as

cession of annular peripheral ribs and then cutting a helical groove or path through the successive ribs, as in a lathe, to develop annular series of teeth with the teeth in one series staggered relative to the teeth in an adjacent annular series.

The teeth 20 and 2| thus generated may also be indicated for the teeth and intervening spaces of a toothed ring l5.

An important advantage of indenting a corrugated paper product with the rolls of Figs. 4 and '7 is that such product or composite sheet may ,be passed continuously at high speed into appropriate pressure-contact with such rolls while minimizing injury of either paper piy through crushing or wrinkling. This is attributable to the fact that the indenting teeth or elements of such rolls break down the corrugations of the corrugated ply along lines substantially perpendicular to the crestvlines of the corrugations and in direct line with the tension exerted on the sheet as it is being drawn or propelled past the indenting teeth. On the other hand, when the corrugations of the corrugated ply are indented crosswise along lines deviating materially from lines running perpendicularly to the crest lines of the corrugations by the use of rolls presenting continuous helical indenting ribs on their peripheries, the tendency is to place the corrugated paper product under stresses such as may cause undesirable distortion or wrinkling of either its plies, particularly,

use of successive indenting rolls with helical ribsrunning in opposite directions, as disclosed in Ives application Ser. No. 173,629, filed November 9, 1937, tends to impose neutralizing strains on thecorrugated paper product, yet even in such case the tendency toward crushing or wrinkling of the piles cannot altogether be overcome while still creating the desired or substantially perfect indentations in the corrugated paper ply by both rolls. It is thus seen that the present invention makes possible worthwhile improvements as regards method, speed of manufacture, and resulting product over Ives Reissue Patent No. 20,034 and Ives application Serial No. 173,629.

It is possible to vary the construction of the roll by which the successive corrugations are indented or locally broken down so that such product is adapted to be flexed readily across its corrugations. In any event, the roll periphery is toothed and its teeth are preferably of a maximum annular span at least substantially equal to the distance between the longitudinal crest I lines of successive corrugations and are preferably spaced from one another a maximum annular distance substantially no greater than the distance between the longitudinal crest lines of successive corrugations; and such teeth occur as successive annular series with the teeth in one series staggered relative to the teeth in an adjacent series and are arranged to indent each of the successive corrugations along lines crossing each of the corrugations substantially perpendicularly at intervals of about to and with the lines of indenture in one corrugation in staggered relationship to the lines of indenture in an adjacent corrugation. The indenting roll is preferably positively driven or rotated at a peripheral speed substantially equal to the linear speed of tin: corrugated paper product or composite sheet 1. An indented, corrugatedpa'per wrapping and packaging material adapted to be flexed aross its corrugations and comprising a corrugated paper ply reinforced by a plane paper ply, the

successive corrugations of said corrugated ply containing indentures along lines crossing said corrugations substantially perpendicularly at intervals in each corrugation or about 1; to /2" and the indentures in each corrugation being arranged instaggered relationship to, and substantially midway between, the indentures in each adjacent corrugation.

2. An indented, corrugated paper wrappin and packaging material adapted to be flexed across its corrugations and comprising a corrugated corrugation being arranged in staggered relationship to, and substantially midway between, the indentures in each adjacent corrugation.

JOHN A. MC EAGE: 

